import java.util.Scanner;

/**
 * Created with IntelliJ IDEA.
 * Description:
 * User:何人亮
 * Date:2024-10-11
 * 15:57
 */
public class Test {
    public static void main(String[] args) {
        Scanner sc=new Scanner(System.in);
        String s=sc.nextLine();
        String[] ss=s.split(" ");
        int sum=0;
        for (int i = 0; i < ss.length; i++) {
            int num=Integer.parseInt(ss[i]);
            num=Math.abs(num);
            sum+=num;
        }
        System.out.println(sum);
    }
}
